Epoxides, for example propylene oxide, have been identified as one of the key oxygen-containing organic compounds. As the process for producing propylene oxide, a process by propylene oxidation in the presence of a catalyst (especially a titanium silicalite) to produce propylene oxide has been commercially available.
However, an olefin catalytic oxidation process of this kind is commonly suffering from a problem as, when the reaction apparatus therefor runs for a period of time, both the activity and the selectivity of the catalyst to the aimed oxidation will decrease, that is, the catalyst will gradually lost its activity during use. At present, it is a common skill to regenerate the spent catalyst. However, this regeneration will result in an increase in the running cost of the apparatus and a decrease in the effectiveness thereof. Further, the regenerated catalyst, when reused, needs a long duration for its activity and selectivity to reach a stable state; and at the same time, operations like increasing the reaction temperature are rendered necessary for a stable reaction, which in turn shortens the service life of the catalyst and lowers its selectivity.
Further, an olefin catalytic oxidation process of this kind commonly suffers a problem as, when the reaction apparatus therefor runs for a period of time, the selectivity of the catalyst to side-reactions will increase, resulting in an increase in the percentage of by-products in the reaction discharge, which necessarily complicates the follow-up separation and purification.
Therefore, there remain needs by the prior art olefin catalytic oxidation process for extending the service life of the catalyst, especially the single-pass service life thereof, and at the same time, suppressing any side-reaction over a prolonged period of time.